This invention relates to fibrous hydrophilic fluff and a method of preparing said fluff wherein an aqueous solution of polymer is formulated into an absorbent composition and then coated on the base fluffing material. The absorbent coated base fluffing material composite is then disintegrated and worked by mechanical means into a plurality of fluff fibers having a high absorption and retention rate.
There are numerous disposable articles in the form of diapers, tampons and the like available on the market which contain a central matrix of absorbent fibrous fluff having varying degrees of absorbency. There are, as well, a large variety of disposable absorbent pads used in institutions such as hospitals including underpads as well as adult and junior diapers. For example, U.S. Pat. No. 3,888,257 illustrates a disposable absorbent article utilizing a powdered polymer dispersed in a wicking substrate useful for the same general purposes as the articles which contain the absorbent hydrophilic fluff of this invention. Fiberized wood pulp alone is not highly efficient. In order to enhance the absorbency of the fiberized wood pulp, water-absorbent polymers have been proposed for distribution within the absorbent matrix.
The conventional fluff matrix construction of the prior known art was fibrous fluff which had been treated with finely divided powdered absorbent polymer. In this regard it has been found that application of the powdered absorbent polymer presented special problems of distribution within the cell matrix, as well as special problems in application. The finely divided powder is very difficult to maintain in anhydrous form while applying it to the fibrous fluff matrix. Presently, the accepted industry practice is to construct a substantially closed system of application in order to minimize the particulate dust which would emanate from the application site. Elaborate systems have been designed for the purpose of containing the absorbent particle dust, yet even a small amount of absorbent powder escaping from the substantially closed system requires special clean-up and maintenance procedures. When the powdered absorbent of the prior known art came in contact with moisture in the plant's atmosphere, it immediately began to swell, thereby yielding a gel which was not easily cleansed away due to its water-absorbent properties. Thus, special solvents were required to maintain the equipment, and more significantly, the surrounding area in which the powdered absorbent dust settled.
The patent to R. E. Erickson et al., U.S. Pat. No. 4,117,184, discloses an absorbent polymer composition having a lightly cross-linked carboxylic polyelectrolyte which has an enhanced absorbent capacity. The difficulty has been in finding a method of evenly distributing the absorbent polymer throughout the fluff matrix. One additional problem has been distributing a sufficient quantity of absorbent polymer into the fluff matrix in order to prepare resultant fluff products with improved absorbent qualities.